This invention is generally directed to processes, and more specifically the present invention is directed to cleaning processes. In one embodiment of the present invention, there is provided a process for cleaning, or removing undesirable debris from imaging members by applying thereto a composition comprised of a styrene butadiene resin, carbon black, magnetite, a polymeric hydroxy compound, or waxes with hydroxyl functionality and a charge control additive. With the process of the present invention there is, for example, enabled the effective removal of magnetite and compositions, such as toners, containing magnetite from layered imaging members. Moreover, the process of the present invention enable the photoconductive imaging member present in an imaging apparatus to function for extended time periods, for example up to 70,000 cycles while simultaneously preventing the localized accumulation of undesirable toner debris thereon which can encompass sufficient areas of the photoconductive members to permit unwanted toner spots to be present on the final developed output copy.
The failure to remove the aforementioned magnetites from layered photoconductive imaging members can result in the formation on the member of an undesirable semi-opaque film, which film can increase the voltage in the background areas of the imaging member, which in turn can increase the amount of toner deposited in non-image areas. This can result in increased copy background and decreased toner yield. Also, the presence of debris particles on the layered imaging member in electrostatic imaging systems can cause undesirable copy quality defects, such as spotting. In embodiments with the process of the present invention, the wax in the toner being applied to the imaging member can capture the magnetite debris particles, which particles can be desirably transported with the toner particles onto the developed copy, into the toner waste sump, and the like.
Cleaning of imaging members with, for example, blades is known. Also known are the cleaning of photoconductive imaging members with brushes. Disadvantages associated with these processes of cleaning include their inability to remove small, for example with a particle size of less than 5 microns, and more specifically from submicron, about 0.01 to 0.9 micron, magnetite rich particles comprised, for example, of toner resin, magnetite, for example from between about 15 and 100 percent magnetite, such as MAPICO BLACK.RTM., pigment particles, charge additives, and the like, from the imaging member. These and other advantges are accomplished with the toner and processes of the present invention.
Developer and toner compositions with certain waxes therein are known. For example, there are disclosed in U.K. Patent Publication 1,442,835 toner compositions containing resin particles, and polyalkylene compounds, such as polyethylene and polypropylene of a molecular weight of from about 1,500 to 6,000, reference page 3, lines 97 to 119, which compositions prevent toner offsetting in electrostatic imaging processes. Additionally, the '835 publication discloses the addition of paraffin waxes together with, or without a metal salt of a fatty acid, reference page 2, lines 55 to 58. In addition, many patents disclose the use of metal salts of fatty acids for incorporation into toner compositions, such as U.S. Pat. No. 3,655,374. Also, it is known that the aforementioned toner compositions with metal salts of fatty acids can be selected for electrostatic imaging methods wherein blade cleaning of the photoreceptor is accomplished, reference U.S. Pat. No. 3,635,704, the disclosure of which is totally incorporated herein by reference. Additionally, there are illustrated in U.S. Pat. No. 3,983,045 three component developer compositions comprising toner particles, a friction reducing material, and a finely divided nonsmearable abrasive material, reference column 4, beginning at line 31. Examples of friction reducing materials include saturated or unsaturated, substituted or unsubstituted fatty acids preferably of from 8 to 35 carbon atoms, or metal salts of such fatty acids; fatty alcohols corresponding to said acids; mono and polyhydric alcohol esters of said acids and corresponding amides; polyethylene glycols and methoxy-polyethylene glycols; terephthalic acids; and the like, reference column 7, lines 13 to 43.
Described in U.S. Pat. No. 4,367,275 are methods of preventing offsetting of electrostatic images of the toner composition to the fuser roll, which toner subsequently offsets to supporting substrates, such as papers, wherein there are selected toner compositions containing specific external lubricants including various waxes, see column 5, lines 32 to 45, which waxes are substantially different in their properties and characteristics than the polymeric alcohol waxes selected for the toner and developer compositions of the present invention; and moreover, the toner compositions of the present invention with the aforementioned polymeric alcohol additives possess advantages such as elimination of toner spotting not achievable with the toner and developer compositions of the '275 patent.
Moreover, toner and developer compositions containing charge enhancing additives, especially additives which impart a positive charge to the toner resin, are well know. Thus, for example, there is described in U.S. Pat. No. 3,893,935 the use of certain quaternary ammonium salts as charge control agents for electrostatic toner compositions. Further, there is illustrated in U.S. Pat. No. 4,338,390, the disclosure of which is totally incorporated herein by reference, developer and toner compositions having incorporated therein as charge enhancing additives organic sulfate and sulfonate compositions; and in U.S. Pat. No. 4,298,672, the disclosure of which is totally incorporated herein by reference, positively charged toner compositions containing resin particles and pigment particles, and as a charge enhancing additive alkyl pyridinium compounds, inclusive of cetyl pyridinium chloride.
Other prior art disclosing positively charged toner compositions with charge enhancing additives include U.S. Pat. Nos. 3,944,493; 4,007,293; 4,079,014; 4,394,430, and 4,937,157, the disclosures of which are totally incorporated herein by reference.